The ratio of peak let-through current Ip to available current is a measure for the current-limiting action of a fuse. The smaller this ratio, the larger the current-limiting action.
Current-limiting action may be enhanced by
A. SUBDIVIDING THE CURRENT PATH OF THE FUSE INTO A LARGE NUMBER OF PARALLEL CURRENT PATHS;
B. COOLING OF THE FUSIBLE ELEMENT BY A FLOW OF COOLING MEDIUM TO CARRY HEAT AWAY BY CONVECTION;
C. MINIMIZING THE THERMAL INSULATION OF THE FUSIBLE ELEMENT, I.E. EXPOSING THE SAME TO THE COOLING MEDIUM ITSELF; AND
D. INCREASING THE TEMPERATURE GRADIENT BETWEEN THE FUSIBLE ELEMENT AND THE COOLING MEDIUM.
It is the prime object of this invention to provide fuses which comply with these requirements. The cost of such equipment is higher than that of prior art equipment, but the result thereof justifies the increase in cost.